Sterile fluids for intravenous (I.V.) administration into the human body often require warming from ambient temperature (20.degree. C.) to approximate body temperature (37.degree. C.) before or during their introduction. The purpose of warming I.V. fluids and chilled blood to approximately 37.degree. C. is to improve the maintenance of body temperature. This is especially true during anesthesia and surgery when body temperature falls due to surgical exposure of large body surface areas to ambient temperature and interference of normal body thermo-regulatory mechanisms by anesthesia. This results in the patient becoming cool, often shivering post-operatively; patients may stay longer in the recovery room to recover from hypothermia.
Current technology to provide warm I.V. fluids to patients undergoing anesthesia and surgery are in-line fluid warmers and external fluid warmers. In-line fluid warmers heat I.V. fluid up to body temperature by applying heat directly (via an in-line heating element) to the I.V. fluid as it passes from the I.V. fluid reservoir (glass bottle or plastic bag) at ambient temperature to the patient. The in-line heating elements for in-line I.V. fluid warmers are disposable and costly per patient use. The disposable cost increases as the maximum flow rate of maintained heated 37.degree. C. I.V. fluid to the patient increases.
External I.V. fluid warmers heat the I.V. fluid (in bulk) to 37.degree. C. before administration to the patient. The external I.V. fluid heaters heat 6 to 20 separate I.V. fluid containers (plastic bags or glass bottles) simultaneously to approximately body temperature. The warmed I.V. bags are removed from the external heater as needed and placed into use, generally by hanging them from an I.V. pole and connecting to an administration set (which usually consist of drip chamber, I.V. tubing, roller clamps & connectors) and finally attaching to the patient's I.V. cannula. After hanging, the warmed I.V. fluid bags cool down toward ambient temperature as time goes by, and further lose temperature as the warmed I.V. fluid passes through the un-heated I.V. administration set at ambient temperature. Slower I.V. fluid flow rates result in cooler delivered I.V. fluids to the patient because the I.V. fluid simply cools down with time while passing through the interconnecting tubing of the administration set, exposed to ambient temperature, before it actually enters the patient. This cooling effect with low I.V. fluid flow rates also affects in-line fluid warmers during passage through the I.V. tubing from in-line warming device to patient. Conversely, I.V. fluid flow rates greater than 100 ml/minute (in external fluid warmers) deliver warmer fluid to the patient, up to bag or reservoir temperature near 37.degree. C.
Advantages exist in preventing heat loss of pre-warmed I.V. fluids during flow through I.V. administration tubing from I.V. reservoir bag or bottle to the patient's anatomic administration site. The use of pre-warmed I.V. fluids can be promoted as a practical, less expensive and more efficient method of administering warm I.V. fluids to patients as opposed to in-line I.V. fluid warmers. Compared to in-line I.V. fluid warmers, pre-warmed I.V. fluids are: 1) less expensive, 2) less complicated to set up and administer, and 3) less bulky because it does not require an active heating source to be placed near the patient.
It is an object of this invention to provide a flexible and transparent insulation device to be attached to I.V. tubing from I.V. reservoir bag or bottle to the patient anatomic administration site.
It is a further object of this invention to use a clear, light-weight insulation material to provide less bulk near the patient and ability to visualize air bubbles in the patient I.V. tubing.
It is a yet a further object of this invention to provide a simple means to attach or insert the patient I.V. tubing into the device.
Other objects and advantages will become apparent in light of the attached drawings and description of the invention presented hereinbelow and the appended claims.